West Nile virus 'escalating rapidly,' with 12 human infections in Larimer County

Aug. 9, 2013

A “rapid increase” this week in reported human cases of West Nile virus in Larimer County has health officials advising people to beware of mosquitoes carrying the potentially devastating disease, according to Larimer County health department.

Twelve residents have been infected, and four of them are showing symptoms such as meningitis, encephalitis and paralysis. Three people in Fort Collins and one in Loveland are showing the severe symptoms, according to the health department.

Cases are expected to rise.

“Unfortunately, by the time a West Nile case is reported to us, it is often three to four weeks past the time a patient was bitten, and two to three weeks past the onset of symptoms,” said health department director Dr. Adrienne LeBailly. “Human cases are reported too late to trigger the most effective interventions when many infected mosquitoes are present in the community.”

The county is among the highest in the United States for severe West Nile virus infections, and it’s had the highest rate in Colorado all month. Elsewhere in the state, a total of 10 other cases had been reported by Friday, according to the state health department’s website.

The risk of severe symptoms increases with age, but all the Larimer County cases have involved people younger than 65, according to the county news release. Two recent Larimer County cases cited on the state website include men ages 52 and 61.

“Beginning the last week of July, the health department made recommendations to Larimer County municipalities on the Front Range to spray for mosquitoes to reduce the risk of West Nile infection,” according to the news release. “Windsor completed citywide spraying last week, and Loveland, which has previously sprayed targeted areas, will be conducting an all-city spraying early next week. Thus far, Fort Collins has elected not to do any spraying, nor has Berthoud.”

More information on local West Nile virus prevalence is available on the county’s website.

The county news release offers these tips for avoiding infection:

• Use a mosquito repellent that has been proven to be effective against West Nile virus-carrying mosquitoes. Ones that contain DEET, picaridin, oil of lemon eucalyptus (with active ingredient PMD, or p-menthane diol) or IR3535 are good choices.

• Keep exposed skin covered or use a repellent when outdoors, especially between dusk and dawn or on cloudy days.

• Drain standing water in your yard or in your garden.

• Add mosquito-eating minnows or a mosquito “dunk” to ornamental ponds that feature still water.